var wangtian;
function test() {
    document.write("任意类型初始值：" + wangtian);
    wangtian = "望天";
    document.write("<p>任意类型：" + wangtian);
    wangtian = 7;
    var name = "\u671B\u72D7\uFF01" + wangtian + "\u53F7";
    document.write("<p>任意类型：" + name);
}
test();
